fix wrong docs for user_lookup variable

xaps.conf

@@ -13,10 +13,10 @@ protocol lmtp {
 plugin {
     # xaps_config contains xaps specific configuration parameters
     # url:              protocol, hostname and port under which xapsd listens
-    # xaps_user_lookup: Use if you want to determine the username used for PNs from environment variables provided by
+    # user_lookup: Use if you want to determine the username used for PNs from environment variables provided by
     #                   login mechanism. Value is variable name to look up.
     # max_retries:      maximum num of retries the http client connects to the xaps daemon
     # timeout_msecs     http timeout of the http connection
-	xaps_config = url=http://localhost:11619 xaps_user_lookup=theattribute max_retries=6 timeout_msecs=5000
+	xaps_config = url=http://localhost:11619 user_lookup=theattribute max_retries=6 timeout_msecs=5000
 	push_notification_driver = xaps
 }